L64105 LSI Logic Corporation, L64105 Datasheet - Page 308

• Manufacturer Part Number: L64105
• Description: Mpeg-2 Audio/video Decoder
• Manufacturer: LSI Logic Corporation

9.6 Display Modes and Vertical Filtering
9-16
To fully understand the display modes and their effects on picture quality,
the following terminology should be understood.
The Display Controller contains a 4-tap luma and a 2-tap chroma vertical
filter. These filters are used to interpolate and reposition luma and
chroma lines to improve picture quality. The interpolation display modes
are provided to double the image size vertically, i.e., to interpolate SIF
(Source Intermediate Format) resolution images to full resolution. The
reposition display modes are provided to improve the quality of the
picture based on the picture type. In addition, the Display Controller can
perform letterbox filtering on both SIF and full-resolution images. The
host can select the display mode by coding the Display Mode bits in
Register 276
specific picture and memory parameters. The paragraphs following the
table include further definitions.
Video Interface
A Progressive Frame is a frame in which all of the data represents
one instance in time. This is based on the encoded bitstream, not
the display system.
An Interlaced Frame contains two fields of data; one field is displayed
before the other. This field is called the first field and may be either
the top or bottom field. There may be motion between the fields.
Chroma Field Repeat implies that the chroma data is field
independent, and the entire chroma data can be repeated in both
field times. Chroma Field Repeat is equivalent to Progressive
Chroma.
Chroma Line Repeat refers to repeating the chroma data on a line
basis. This is one method of converting from 4:2:0 to 4:2:2 video
format (chroma repositioning is the other method). Chroma Line
Repeat is equivalent to Interlaced Chroma, assuming that the
chroma data is not field repeated as well.
(page
4-63).
Table 9.5
correlates the display modes to